Researchers Test Emergency Exit Signs for Tunnels

About 15 years ago, several catastrophic, deadly highway tunnel disasters occurred in Europe. As a result, researchers began to evaluate methods to more effectively help stranded motorists reach emergency exits. The green “running man” sign — an international symbol for “emergency exit” — was adopted to help communicate with motorists. The United States has yet to adopt its widespread use.

In a project for the National Cooperative Highway Research Program, the Texas A&M Transportation Institute (TTI) is testing the effectiveness of the sign in the event of a tunnel disaster.

“There is currently no uniform system or strategy used in U.S. tunnels to guide drivers when an emergency happens,” says TTI Associate Research Scientist Laura Higgins. According to Higgins, project supervisor, emergency vehicles and personnel are often unable to reach stranded motorists in a tunnel due to other vehicles.

“We addressed two major questions,” says Higgins. “How do you let people trapped in a tunnel know they need to leave their vehicles to evacuate, and how do you direct them to emergency exits in an environment where there may be smoke and reduced visibility?”

The team constructed a 60-foot tunnel inside TTI’s Environmental and Emissions Research Facility and presented 63 participants with different emergency response scenarios to gauge their reactions. Researchers used different types of sign lighting, from backlit-with-LED signs to glow-in-the-dark signs. The tunnel also had pathways marked by LED lights, which alternated between a steady glow and flashing sequentially in the direction of the exit. Researchers added artificial smoke to the tunnel so participants could assess the signs and lighted pathways for best visibility.

“We have the data; now we’re working on the analysis,” notes Higgins. “The encouraging thing is that the majority of the participants understood the green running man symbol.”

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“We addressed two major questions: how do you let people trapped in a tunnel know they need to leave their vehicles to evacuate, and how do you direct them to emergency exits in an environment where there may be smoke and reduced visibility?”Laura Higgins. TTI Associate Research Scientist